Create and use a new GzipPacked class, also when sending

telethon/network/mtproto_sender.py

@@ -9,7 +9,7 @@ from ..errors import (
     rpc_message_to_error
 )
 from ..extensions import BinaryReader, BinaryWriter
-from ..tl import MessageContainer
+from ..tl import MessageContainer, GzipPacked
 from ..tl.all_tlobjects import tlobjects
 from ..tl.types import MsgsAck
 
@@ -68,10 +68,12 @@ class MtProtoSender:
         self._pending_receive.extend(requests)
         if len(requests) == 1:
             request = requests[0]
+            data = GzipPacked.gzip_if_smaller(request)
         else:
             request = MessageContainer(self.session, requests)
+            data = request.to_bytes()
 
-        self._send_packet(request.to_bytes(), request)
+        self._send_packet(data, request)
 
     def _send_acknowledges(self):
         """Sends a messages acknowledge for all those who _need_confirmation"""
@@ -376,11 +378,7 @@ class MtProtoSender:
 
     def _handle_gzip_packed(self, msg_id, sequence, reader, state):
         self._logger.debug('Handling gzip packed data')
-        reader.read_int(signed=False)  # code
-        packed_data = reader.tgread_bytes()
-        unpacked_data = gzip.decompress(packed_data)
-
-        with BinaryReader(unpacked_data) as compressed_reader:
+        with BinaryReader(GzipPacked.read(reader)) as compressed_reader:
             return self._process_msg(msg_id, sequence, compressed_reader, state)
 
     # endregion

telethon/tl/__init__.py

@@ -1,3 +1,4 @@
 from .tlobject import TLObject
 from .session import Session
+from .gzip_packed import GzipPacked
 from .message_container import MessageContainer

telethon/tl/gzip_packed.py

@@ -0,0 +1,40 @@
+import gzip
+
+from . import TLObject
+from ..extensions import BinaryWriter
+
+
+class GzipPacked(TLObject):
+    constructor_id = 0x3072cfa1
+
+    def __init__(self, data):
+        super().__init__()
+        self.data = data
+
+    @staticmethod
+    def gzip_if_smaller(request):
+        """Calls request.to_bytes(), and based on a certain threshold,
+           optionally gzips the resulting data. If the gzipped data is
+           smaller than the original byte array, this is returned instead.
+
+           Note that this only applies to content related requests.
+        """
+        data = request.to_bytes()
+        # TODO This threshold could be configurable
+        if request.content_related and len(data) > 512:
+            gzipped = GzipPacked(data).to_bytes()
+            return gzipped if len(gzipped) < len(data) else data
+        else:
+            return data
+
+    def to_bytes(self):
+        # TODO Maybe compress level could be an option
+        with BinaryWriter() as writer:
+            writer.write_int(GzipPacked.constructor_id, signed=False)
+            writer.tgwrite_bytes(gzip.compress(self.data))
+            return writer.get_bytes()
+
+    @staticmethod
+    def read(reader):
+        reader.read_int(signed=False)  # code
+        return gzip.decompress(reader.tgread_bytes())

telethon/tl/message_container.py

@@ -1,4 +1,4 @@
-from . import TLObject
+from . import TLObject, GzipPacked
 from ..extensions import BinaryWriter
 
 
@@ -24,7 +24,8 @@ class MessageContainer(TLObject):
             writer.write_int(
                 self.session.generate_sequence(x.content_related)
             )
-            packet = x.to_bytes()
+
+            packet = GzipPacked.gzip_if_smaller(x)
             writer.write_int(len(packet))
             writer.write(packet)